我的任务是制作自己的Sobel方法，而不是使用OpenCV中发现的cv::Sobel。我试着实现一个我在Programming techniques
当我运行程序时，cv::Mat抛出了一个错误。有人知道为什么吗?
Sobel方法:
int sobelCorrelation(Mat InputArray, int x, int y, String xory)
{
if (xory == "x") {
return InputArray.at<uchar>(y - 1, x - 1) +
2 * InputArray.at<uchar>(y, x - 1) +
InputArray.at<uchar>(y + 1, x - 1) -
InputArray.at<uchar>(y - 1, x + 1) -
2 * InputArray.at<uchar>(y, x + 1) -
InputArray.at<uchar>(y + 1, x + 1);
}
else if (xory == "y")
{
return InputArray.at<uchar>(y - 1, x - 1) +
2 * InputArray.at<uchar>(y - 1, x) +
InputArray.at<uchar>(y - 1, x + 1) -
InputArray.at<uchar>(y + 1, x - 1) -
2 * InputArray.at<uchar>(y + 1, x) -
InputArray.at<uchar>(y + 1, x + 1);
}
else
{
return 0;
}
}
在另一个函数中调用和处理它:
void imageOutput(Mat image, String path) {
image = imread(path, 0);
Mat dst;
dst = image.clone();
int sum, gx, gy;
if (image.data && !image.empty()){
for (int y = 0; y < image.rows; y++)
for (int x = 0; x < image.cols; x++)
dst.at<uchar>(y, x) = 0.0;
for (int y = 1; y < image.rows - 1; ++y) {
for (int x = 1; x < image.cols - 1; ++x){
gx = sobelCorrelation(image, x, y, "x");
gy = sobelCorrelation(image, x, y, "y");
sum = absVal(gx) + absVal(gy);
if (sum > 255)
sum = 255;
else if (sum < 0)
sum = 0;
dst.at<uchar>(x, y) = sum;
}
}
namedWindow("Original");
imshow("Original", image);
namedWindow("Diagonal Edges");
imshow("Diagonal Edges", dst);
}
waitKey(0);
}
int main(int argc, char* argv[]) {
Mat image;
imageOutput(image, "C:/Dropbox/2-falling-toast-ted-kinsman.jpg");
return 0;
}
int absVal(int v)
{
return v*((v < 0)*(-1) + (v > 0));
}
运行时抛出以下错误:
Unhandled exception at 0x00007FFC9365A1C8 in Miniproject01.exe: Microsoft C++ exception: cv::Exception at memory location 0x000000A780A4F110.
和指向这里:
template<typename _Tp> inline
_Tp& Mat::at(int i0, int i1)
{
CV_DbgAssert( dims <= 2 && data && (unsigned)i0 < (unsigned)size.p[0] &&
(unsigned)(i1 * DataType<_Tp>::channels) < (unsigned)(size.p[1] * channels()) &&
CV_ELEM_SIZE1(DataType<_Tp>::depth) == elemSize1());
return ((_Tp*)(data + step.p[0] * i0))[i1];
}
如果任何人有任何建议或想法，我做错了，这将是非常感激!
此代码片段演示如何计算将图像与索贝尔核卷积的索贝尔3x3导数。您可以很容易地扩展到不同的内核大小，将内核半径作为my_sobel的输入，并创建适当的内核。
#include <opencv2opencv.hpp>
#include <iostream>
using namespace std;
using namespace cv;
void my_sobel(const Mat1b& src, Mat1s& dst, int direction)
{
Mat1s kernel;
int radius = 0;
// Create the kernel
if (direction == 0)
{
// Sobel 3x3 X kernel
kernel = (Mat1s(3,3) << -1, 0, +1, -2, 0, +2, -1, 0, +1);
radius = 1;
}
else
{
// Sobel 3x3 Y kernel
kernel = (Mat1s(3, 3) << -1, -2, -1, 0, 0, 0, +1, +2, +1);
radius = 1;
}
// Handle border issues
Mat1b _src;
copyMakeBorder(src, _src, radius, radius, radius, radius, BORDER_REFLECT101);
// Create output matrix
dst.create(src.rows, src.cols);
// Convolution loop
// Iterate on image
for (int r = radius; r < _src.rows - radius; ++r)
{
for (int c = radius; c < _src.cols - radius; ++c)
{
short s = 0;
// Iterate on kernel
for (int i = -radius; i <= radius; ++i)
{
for (int j = -radius; j <= radius; ++j)
{
s += _src(r + i, c + j) * kernel(i + radius, j + radius);
}
}
dst(r - radius, c - radius) = s;
}
}
}
int main(void)
{
Mat1b img = imread("path_to_image", IMREAD_GRAYSCALE);
// Compute custom Sobel 3x3 derivatives
Mat1s sx, sy;
my_sobel(img, sx, 0);
my_sobel(img, sy, 1);
// Edges L1 norm
Mat1b edges_L1;
absdiff(sx, sy, edges_L1);
// Check results against OpenCV
Mat1s cvsx,cvsy;
Sobel(img, cvsx, CV_16S, 1, 0);
Sobel(img, cvsy, CV_16S, 0, 1);
Mat1b cvedges_L1;
absdiff(cvsx, cvsy, cvedges_L1);
Mat diff_L1;
absdiff(edges_L1, cvedges_L1, diff_L1);
cout << "Number of different pixels: " << countNonZero(diff_L1) << endl;
return 0;
}
如果我是你，我几乎总是避免使用for循环(如果可能的话)。不必要的for循环往往会减慢执行速度。相反，尽可能重用。例如，下面的代码使用filter2D给出2d关联结果:
Mat kern = (Mat_<float>(3,3)<<-1,0,1,-2,0,2,-1,0,1);
Mat dest;
cv::filter2D(src,dest,src.type(),kern);
如果你想得到卷积结果，你需要在过滤之前翻转内核'kern'。
cv::flip(kern,kern, -1);
如果你想挤出更多的性能，你可以使用可分离过滤器'sepFilter2D'
谢谢!我能够使用上面的内核生成渐变地图，并使用openCV代码filter2D从使用自定义内核在opencv 2DFilter -导致崩溃…卷积如何?
将图像与内核进行卷积。我使用的代码是
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
using namespace cv;
using namespace std;
int main(int argc, char** argv) {
//Loading the source image
Mat src;
//src = imread("1.png");
src = cv::imread("E:\Gray_Image.bmp", 0);
//Output image of the same size and the same number of channels as src.
Mat dst1,dst2,grad;
//Mat dst = src.clone(); //didn't help...
//desired depth of the destination image
//negative so dst will be the same as src.depth()
int ddepth = -1;
//the convolution kernel, a single-channel floating point matrix:
//Mat kernel = imread("kernel.png");
Mat kernel_x = (Mat_<float>(3, 3) << -1, 0, 1, -2, 0, 2, -1, 0, 1);
Mat kernel_y = (Mat_<float>(3, 3) << -1, -2, -1, 0, 0, 0, 1, 2, 1);
kernel_x.convertTo(kernel_x, CV_32F); kernel_y.convertTo(kernel_y, CV_32F); //<<not working
//normalize(kernel, kernel, 1.0, 0.0, 4, -1, noArray()); //doesn't help
//cout << kernel.size() << endl; // ... gives 11, 11
//however, the example from tutorial that does work:
//kernel = Mat::ones( 11, 11, CV_32F )/ (float)(11*11);
//default value (-1,-1) here means that the anchor is at the kernel center.
Point anchor = Point(-1, -1);
//value added to the filtered pixels before storing them in dst.
double delta = 0;
//alright, let's do this...
filter2D(src, dst1, ddepth, kernel_x, anchor, delta, BORDER_DEFAULT);
filter2D(src, dst2, ddepth, kernel_y, anchor, delta, BORDER_DEFAULT);
imshow("Source", src); //<< unhandled exception here
//imshow("Kernel1", kernel_x); imshow("Kernel2", kernel_y);
imshow("Destination1", dst1);
imshow("Destination2", dst2);
addWeighted(dst1, 0.5, dst2, 0.5, 0, grad);
imshow("Destination3", grad);
waitKey(1000000);
return 0;
}